Manufacture of micro electro mechanical systems (MEMS) using a focused ion beam (FIB) apparatus has been put to practical use. The focused ion beam apparatus processes micro-electro-mechanical-systems while irradiating a wide range of field-of-view with a focused ion beam.
By the way, in the focused ion beam apparatus, when a focused ion beam is deflected and the irradiation point of the focused ion beam is away from the center of the beam axis, distortion of the focused ion beam occurs. Due to such distortion of the focused ion beam, non-uniformity of the processing shape occurs.
Therefore, there is also a focused ion beam apparatus which has a function called dynamic focus, suppresses distortion of the focused ion beam in a single field-of-view, and reduces non-uniformity of the processing shape. The dynamic focus means setting optimal values of focus of the focused ion beam and stigmatic focus at each position in the single field-of-view point in advance and dynamically controlling the focus and the stigmatic focus during movement of the beam irradiation point.
For example, PTL 1 discloses a charged particle beam lithographic apparatus that realizes a lithographic apparatus in which there is no difference in line width between the x-direction and the y-direction regardless of deflection coma aberration and deflection chromatic aberration.
Specifically, the charged particle beam lithographic apparatus includes a beam correction unit for carrying out the dynamic focal correction and the dynamic astigmatic correction by adding respectively a focal deviation amount and an astigmatic deviation amount for eliminating the difference between the x-direction and the y-direction of beam blurring, caused by the deflection coma aberration and the deflection chromatic aberration, to a correction value for the dynamic focal correction and a correction value for the dynamic astigmatic correction.
Further, PTL 2 discloses a charged particle beam apparatus which has high resolving power and a wide scanning region (observation field-of-view).
Specifically, the charged particle beam apparatus includes a unit for adjusting the focus, a unit for adjusting astigmatism, a unit for controlling and detecting scanning positions, and a unit for controlling the focus adjustment and astigmatism adjustment at a time in conjunction with the scanning position.